This present invention relates to a telephoto lens having an F number of the order of 1:4 and an image covering angle of the order of 12.degree..
Various conditions for making telephoto lenses with the above-described features small in size are disclosed in Japanese Laid-Open Patent Publication No. 53-27422. The lens described in the Publication No. 53-27422 has an increased residual spherical aberration which affects the peripheral edge of an image plane. This lowers the contrast of the low-frequency components of an image, resulting in a poorer focusing performance than expected.